LEMON Manuals: Even more car manuals for everyone
Home >> Toyota >> 2012 >> Highlander Hybrid >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 127 (Air Conditioning (Manual) (Diagnostic Codes & Circuit Tests) (Except Hybrid)) >> AIR CONDITIONING SYSTEM (for Manual Air Conditioning System) >> Circuit Tests >> PTC Heater Circuit >> Procedure

PTC Heater Circuit: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. INSPECT FUSE (PTC NO. 1, PTC NO. 2, PTC NO. 3) 
    1. Remove the PTC NO. 1, PTC NO. 2 and PTC NO. 3 fuses from the engine room No. 2 relay block.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      PTC NO. 1 Always Below 1Ω
      PTC NO. 2 Always Below 1Ω
      PTC NO. 2 Always Below 1Ω

    NG → REPLACE FUSE 

    OK: Go to next step 

  2. INSPECT PTC HEATER RELAY 
    1. Remove the PTC HTR1, PTC HTR2 and PTC HTR3 relays from the engine room No. 2 relay block.
      Fig 1: Identifying PTC Heater Relay
      GTY187597Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance of the relays.

      Standard resistance

      Tester Connection Condition Specified Condition
      3 - 5 when battery voltage is not applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 when battery voltage is applied to terminals 1 and 2 Below 1 Ω

    NG → REPLACE PTC HEATER RELAY 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BODY GROUND) 
    1. Remove the PTC HTR1, PTC HTR2 and PTC HTR3 relays from the engine room No. 2 relay block.
      Fig 2: Identifying PTC HTR1, PTC HTR2 And PTC HTR3 Relays From The Engine Room No. 2 Relay Block
      GTY306805Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      PTC HTR1 relay terminal 2 - Body ground Always Below 1 Ω
      PTC HTR2 relay terminal 2 - Body ground Always Below 1 Ω
      PTC HTR3 relay terminal 2 - Body ground Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - PTC HEATER RELAY) 
    1. Remove the PTC HTR1, PTC HTR2 and PTC HTR3 relays from the engine room No. 2 relay block.
      Fig 3: Identifying PTC HTR1, PTC HTR2 And PTC HTR3 Relays From The Engine Room No. 2 Relay Block
      GTY301265Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the ignition switch on (IG).
    3. When the PTC heater operating conditions are met (engine at idling speed or faster, ambient temperature is 10°C (50°F) or less, engine coolant temperature is 65°C (149°F) or less, set temperature switch is set to MAX HOT), turn the blower switch to the Lo setting.
    4. Measure the voltage according to the value(s) in the table below.

      Standard voltage

      Tester Connection Condition Specified Condition
      PTC HTR1 relay terminal 1 - Body ground Always 11 to 14 V
      PTC HTR2 relay terminal 1 - Body ground Always 11 to 14 V
      PTC HTR3 relay terminal 1 - Body ground Always 11 to 14 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. CHECK HARNESS AND CONNECTOR (BATTERY - PTC HEATER RELAY) 
    1. Remove the PTC HTR1, PTC HTR2 and PTC HTR3 relays from the engine room No. 2 relay block.
      Fig 4: Identifying PTC HTR1, PTC HTR2 And PTC HTR3 Relays From The Engine Room No. 2 Relay Block
      GTY301264Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage

      Tester Connection Condition Specified Condition
      PTC HTR1 relay terminal 5 - Body ground Always 11 to 14 V
      PTC HTR2 relay terminal 5 - Body ground Always 11 to 14 V
      PTC HTR3 relay terminal 5 - Body ground Always 11 to 14 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  6. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - PTC HEATER) 
    1. Remove the PTC HTR1, PTC HTR2 and PTC HTR3 relays from the engine room No. 2 relay block.
      Fig 5: Identifying PTC HTR1, PTC HTR2 And PTC HTR3 Relays From The Engine Room No. 2 Relay Block
      GTY304392Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      PTC HTR1 relay terminal 3 - D44-2 (B) Always Below 1 Ω
      PTC HTR2 relay terminal 3 - D44-3 (B) Always Below 1 Ω
      PTC HTR3 relay terminal 3 - D44-1 (B) Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  7. CHECK AIR CONDITIONING AMPLIFIER 
    1. Remove the air conditioning amplifier with its connectors still connected. Refer to REMOVAL - Step 6 .
      Fig 6: Identifying Air Conditioning Amplifier
      GTY307572Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the ignition switch on (IG).
    3. When the PTC heater operating conditions are met (engine at idling speed or faster, ambient temperature is 10°C (50°F) or less, engine coolant temperature is 65°C (149°F) or less, set temperature switch is set to MAX HOT), turn the blower switch to the Lo setting.
    4. Measure the voltage according to the value(s) in the table below.

      Standard voltage

      Tester Connection Condition Specified Condition
      D37-3 (PTC1) - Body ground Always 11 to 14 V
      D37-22 (PTC2) - Body ground Always 11 to 14 V
      D37-4 (PTC3) - Body ground Always 11 to 14 V

    NG → REPLACE AIR CONDITIONING AMPLIFIER 

    OK: Go to next step 

  8. REPLACE PTC HEATER 
    1. Replace the PTC heater. Refer to REMOVAL - Step 17

    NEXT: Go to next step 

  9. CHECK PTC HEATER (OPERATION) 
    1. Operate the PTC heater to check that functions properly.

      OK

      PTC heater function operates normally.

    NG → See step   10 

    OK → END (PTC HEATER IS DEFECTIVE) 

  10. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE 
scientia non olet · About LEMON Manuals